1. Field Of The Invention
The invention is directed to an improved a stator with a rotary current winding, a brushless direct current machine having a stator, a shaped part for winding guidance for a stator with a rotary current winding, and a winding method for producing a stator with a rotary current winding.
2. Description of the Prior Art
In the manufacture of rotary current machines, such as motors or generators, the problem arises that the three phase coils of the stator winding must be placed individually and in succession, overlapping on the order of roof tiles, in the slots of the stator iron packet, if a uniform coil layer, high slot filling, and thus maximum efficiency are to be attained. The known method of winding one phase layer for each pole and then depositing its conductor wire uninterruptedly, creating a wire intersection with the second conductor wire and winding its phase coil, and then repeating the entire process again for the third phase coil, makes mass production uneconomical.
Plug-in windings, in which individual conductor loops are connected after insertion in slots, are also not feasible if there are relatively high numbers of conductors and/or poles, because there are too many connection points for electrical contacting means. Winding techniques that provide for the separate winding and subsequent joining together of the individual phases that are embodied as winding packets have disadvantages, because of the nonuniformity of the winding and the virtually unavoidable line intersections, that have an effect on the power, efficiency, and service life of the machine.
In the manufacture of a pull-in winding, the coils are wound either individually or jointly on a winding frame and then, with the aid of a pull-in device, pulled jointly or sequentially into the stator. The slot slits must then be closed with suitable wedges in a further operation, to prevent individual wires from escaping from the slots. Producing a pull-in winding requires relatively long production times, since the individual coils must be wound onto separate frames in a first work step. In a second work step, these prefabricated coils are transferred to the pull-in tool and then pulled into the stator in a further operation.
A further production method that is often employed comprises winding the winding directly into the stator slots with the aid of a so-called needle winder. For production reasons, however, the winding must be embodied such that the winding heads of the stator coils on the face ends do not overlap, and that there are no intersections whatever in the area of the winding head. The nonintersecting winding heads produced in this way are so-called toothed coil windings. However, they have electrically unfavorable properties, since their cross-sectional area is limited to approximately two-thirds of the maximum possible cross-sectional area. The applicable winding must therefore have more windings and hence more copper, which means increased consumption of material.